Validation of the Danish version of the disease specific instrument EORTC QLQ-CR38 to assess Health-related quality of life in patients with colorectal cancer

Background: The European Organisation for Research and Treatment of Cancer (EORTC) quality of life colorectal questionnaire module (QLQ-CR38) was developed in 1999, and an update, the QLQ-CR29 was published recently. To date the Danish version of the questionnaire has not been validated. The aim of this study was to examine the psychometric properties of the Danish version of EORTC QLQ-CR38. Methods: EORTC QLQ-CR38 was administered to 190 patients with colorectal cancer in two Danish hospitals, one month after their operation. A psychometric evaluation of the questionnaire's structure, reliability, convergent, divergent and known-groups validity was performed. Results: Data from 164 (86.3%) patients were available for analysis. The Danish version of EORTC QLQ-CR38 showed satisfactory psychometric properties for the scales: body image, sexual functioning, male sexual problems and defecations problems. Suboptimal psychometric performances were found for the scales: micturition problems, symptoms of the gastrointestinal tract and weight loss. Evaluation of the psychometric properties of the scale chemotherapy side effects was limited by the low number of patients receiving chemotherapy. It was not possible to assess the psychometric properties of the scale female sexual problems and the single item sexual enjoyment due to a high number of missing values. The homogeneity of the study population made the evaluation of known-group validity difficult. Conclusions: The results of this study suggest that the validity of the Danish version of EORTC QLQ-CR38 is acceptable. Furthermore, the results support the appropriateness of the updated version, the EORTC QLQ-CR29.